The Regents of the University of Colorado, a body corporate, contracting on behalfof the University of Colorado at Boulder for the benefit of INSTAAR

Note on the Behavior of Beluga Whales Feeding on CapelinAuthor(s): P. D. Watts and B. A. DraperSource: Arctic and Alpine Research, Vol. 18, No. 4 (Nov., 1986), p. 439Published by: INSTAAR, University of ColoradoStable URL: http://www.jstor.org/stable/1551093 .

Accessed: 15/06/2014 00:06

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.

.

INSTAAR, University of Colorado and The Regents of the University of Colorado, a body corporate,contracting on behalf of the University of Colorado at Boulder for the benefit of INSTAAR are collaboratingwith JSTOR to digitize, preserve and extend access to Arctic and Alpine Research.

http://www.jstor.org

This content downloaded from 185.2.32.49 on Sun, 15 Jun 2014 00:06:44 AMAll use subject to JSTOR Terms and Conditions

Arctic and Alpine Research, Vol. 18, No. 4, 1986, p. 439

NOTE ON THE BEHAVIOR OF BELUGA WHALES FEEDING ON CAPELIN

P. D. WATTS AND B. A. DRAPER Institute of Arctic Ecophysiology, Box 1928

Churchill, Manitoba, Canada ROB OEO

ABSTRACT

Beluga whales were observed executing tight circles and half circles in response to avoidance by capelin. Individual beluga were observed capturing capelin in their mouth.

The beluga whale (Deliphinapterus leucas) population of western Hudson Bay has been reported to number 10,000 (Sergeant, 1973). During the summer months, large numbers of beluga are found in a few specific river estu- aries throughout the Arctic (Fraker et al., 1979). The Churchill River estuary is a major concentration area for the Hudson Bay population. The estuary is also used by the Canadian government as a port for shipping grain. Beluga whales were observed feeding on capelin in the dredged section of the Churchill harbor. The depth of water in the observation area ranged from 9.7 to 11.2 m, depending on the tide. Water temperatures ranged from 2 to 16?C. A walkway 30 m above the Churchill dock was used as an observation post. Binoculars were used to observe whales between 0600 and 1800 at various tide levels during the summer of 1982. Inuit hunting of the beluga did not occur close to the observation site and boat ac- tivity was minimal due to the late start of the Churchill shipping season.

Beluga were observed to pursue, capture, and ingest capelin (Mallotus villosus). Previous descriptions of feed- ing behavior in this species have not included confirma- tion that ingestion was occurring. Pippard and Malcolm (1978) considered beluga to be feeding when they were seen to execute tight circles and half circles in a restricted area. Fraker et al. (1979) considered feeding to be indicated by diving in a restricted area with gulls present. Capelin are an important prey species for the beluga (Kleinenberg et al., 1964; Sergeant, 1973). In the present work, beluga were observed to execute tight circles and frequent changes of direction as they pursued and captured capelin.

Each chase sequence was initiated with the beluga swim- ming on its side beneath a shoal of capelin. The predator swam in tight circles or half circles and frequently changed direction in near synchrony with the prey. Individual beluga were observed moving towards the surface and clos- ing their mouths on the capelin. Once capture had oc- curred, the whale would expel water from the mouth and then submerge and move off. When an attack was suc-

cessful, pursuit of the capelin shoal was usually discon- tinued. In some cases a second chase sequence was initiated. Prey were captured both at the surface and below the surface of the estuary waters. Capelin sometimes jumped out of the water during a chase sequence, which was interpreted as an attempt to avoid capture. An exami- nation of stomach contents from beluga harvested in the Churchill River by local Inuit hunters confirmed that capelin were ingested. Arctic terns (Sterna paradisaea) were also observed feeding on capelin in the area where an indi- vidual or a group of beluga were hunting. To delineate the significance of summer feeding in the yearly energy budget of the beluga, further information on the rate of food ingestion and energy demands are required.

ACKNOWLEDGMENT

We wish to thank Ports Canada, Churchill, for their coopera- tion in conducting the study.

REFERENCES CITED

Fraker, M. A., Gordon, C. D., McDonald, J. W., Ford, J. K. B., and G. Cambers, 1979: White whale (Delphinapterus leucas) distribution and abundance and the relationship to physical and chemical characteristics of the Mackenzie Estuary. Canada Fisheries and Marine Service Technical Report, 863. 56 pp.

Kleinenberg, S. E., Yablokov, A. V., Bel'kovich, B. M., and Tara- sevich, M. N., 1964: Beluga (Delphinapterus leucas): Investi- gation of the Species. Jerusalem: Israel Program for Scien- tific Translations. 376 pp.

Pippard, L. and Malcolm, H., 1978: White whales: Observations on their distribution, population and critical habitats in the St. Lawrence and Saquenay River. Unpublished report for Department of Indian and Northern Affairs, Ottawa. Con- tract 76-190. 160 pp.

Sergeant, D. E., 1973: Biology of white whales (Delphinapterus leucas) in western Hudson Bay. Journal of Fisheries Research Board of Canada, 30: 1065-1090.

Ms submitted February 1986

?1986 Regents of the University of Colorado P. D. WATTS AND B. A. DRAPER / 439

This content downloaded from 185.2.32.49 on Sun, 15 Jun 2014 00:06:44 AMAll use subject to JSTOR Terms and Conditions